The version from ISO 2019 supersedes the 2006 edition. Major changes include:
If you have been searching for the term , you are likely past the basics. You need the technical meat: the test methods, the metrology, and the step-by-step procedures to prove that your cleanroom truly meets its claimed ISO class. Iso 14644-3.pdf
How fast can your room return to its target cleanliness after a contamination event? This is critical for cleanrooms that are "at rest" most of the time. The standard defines recovery factors (e.g., 100x, 10x reduction time). The version from ISO 2019 supersedes the 2006 edition